scb-68 digital pin outputs incorrect values

[Ayin]

Hi all,

I'm using a SCB-68 connected to a PCI-MIO-16E-4. I just want to use the digital pin on the SCB-68 to otuput high/low signals. I'm testing the device in the "Measurement&Automation Explorer", under "Test Panels".

The Analog Output works as expected and outputs the entered voltage values.

The Digital pins, however, give me really strange values. When I configure port0 to "all output", the voltage measured at the all the digital pins is 4.54V, regardless of whether my selected state is "all high" or "all low", with the exception of pin19/DIO4, which always gives me 0V.

Is this expected? What are some possible solutions?

Thanks,

A

[Dennis_Knutson · Accepted solution]

No, it's not normal, assuming you are measuring from a digital output and referenced to dgnd. Does it pass self-test? The board is an old model. Who used it before you? It could easily have been damaged. Taking the scb-68 and cable out of the picture, have you looked at the DAQ card output with nothing connected? How about the end of the cable without the scb-68 connected?

[Ayin]

Thanks for the quick reply! What is the self-test?

The board have indeed been used for a while, but it has been able to perform experiments successfully previously. So you think it might be the board that's damaged? How can I confirm that?

I will look at the outputs of the board withn nothing connected tomorrow.

[Dennis_Knutson]

In MAX, there is a self-test button.

You confirm the board is at fault by testing it as I mentioned.

[Ayin]

Alright, turns out the card was indeed faulty after testing the output at the pins.

One other question, I'm having the digital out connecting to an opamp to control a motor. However, when I connected the V+ line to the pin, and the gnd to DGND, I'm only seeing around 1.6V across the digital pin pair. What's the correct way to wire this?